1. Field of the Invention
This invention relates to an image processing apparatus, an image processing method and a program that can suitably be applicable to, for instance, an authentication apparatus for biometrically authenticating one or more than one blood vessels of a living body.
2. Description of the Related Art
Authentication apparatus of this kind are adapted to pick up an image of blood vessels, utilizing the property of deoxidized hemoglobin (venous blood) or oxidized hemoglobin (arterial blood) of singularly absorbing rays of the near infrared band (near infrared radiation), and collate the image with the blood vessel images registered in a memory as data for collation.
However, the quantity of light irradiated on a blood vessel per unit area can vary to give rise to an unclear blood vessel image as a function of the variations because blood vessels are three-dimensionally intricately arranged in the inside of the living body.
For this reason, a filtering process that is referred to as Laplacian is typically conducted in authentication apparatus of this kind. With such a filtering process, the edges of blood vessels are emphasized in the obtained image to improve the image quality (see, inter alia, Pat. Document 1: Jpn. Pat. Appln. Laid-Open Publication No. 2003-150934).